From the given statement, select the definition, property, postulate, or theorem that justifies this proven statement.
a. if a line through the center of the circle is perpendicular to a chord, it also bisects the chord.
b. in the same circle, all chords are congruent.
c. in the same circle, all radii are congruent.
d. in the same circle, if any radii are perpendicular to two chords, then the chords are congruent.
e. in the same circle, chords equidistant from the center of the circle are congruent.